Printing apparatus and method



July 20, 1965 E. D. NYSTRAND PRINTING APPARATUS AND METHOD 5 Sheets-Sheet 1 Filed Dec. 3, 1963 July 20, 1965 E. D. NYSTRAND 3,195,458

PRINTING APPARATUS AND METHOD Filed Dec. 3. 1963 3 Sheets-Sheet 2 y 1965 E. D. NYSTRAND 3,

P ARATU Filed De. s. 1963 s Sheets-Sheet a United States Patent 3,195,458 PRTNTKNG APPARATUS AND METHGD Ernst Daniel Nystrand, Green Bay, Wis., assignor to Paper (Ionverting Machine (10., inc, Green Bay, Wis., a corporation of Wisconsin Filed Dec. 3, 1963, Ser. No. 327,711 6 Claims. (61. 101- 1151) This invention relates to printing apparatus, and, more particularly, to printing utilizing a flexible plate wrapped around a plate cylinder.

Thin flexible plates have been utilized before, but there has been a continuing problem of satisfactorily securing the plates against both deformation and movement. This invention provides apparatus which operates in a novel fashion to utilize movement to correct distortion and thus supply a faithful reproduction of the printed matter. The provision of apparatus that operates in a novel fashion to tension thin printing plates thus constitutes an important object of the invention.

Another object of the invention is to provide a novel combination of elements effectively utilizing such a flexible plate.

A further object of the invention is to provide a method for fastening of thin printing plates for rotary printing where the gap in printing between repeats is kept to a bare minimum.

Still another object of the invention is to provide a novel method of printing wherein the above-mentioned flexible plate is handled and used in a unique manner to provide superior printing.

The invention finds advantageous use in connection with high speed printing of office forms and like material. In such an environment, relatively short orders are common. Through the invention, quick and inexpensive replacement of the printing plates is facilitated, and this is especially important where the plate rolls are of relatively small diameter, i.e., carrying a single repeat of the order of 8"11".

Other objects and advantages of the invention may be seen in the details of construction and operation set down in this specification.

The invention is explained in conjunction with an illustrative embodiment in the accompanying drawing, in which- FIG. 1 is a fragmentary elevational view of a press utilizing the invention;

FIG. 2 is a fragmentary elevational view, partially in section, of the plate cylinder utilized in the invention;

FIG. 3 is a fragmentary perspective view of the printing plate prior to the installation thereof on the plate cylinder of FIG. 2;

FIG. 4 is an enlarged fragmentary end elevational view taken along the line 4-4 of FIG. 2;

FIG. 5 is a fragmentary sectional view taken along the line 55 of FIG. 4;

FIG. 6 is a fragmentary sectional view taken along the line 6--6 of FIG. 5;

FIG. 7 is a fragmentary sectional view taken along the line 77 of FIG. 5;

FIG. 8 is a fragmentary detail sectional view through a part of the plate cylinder of FIG. 2 and showing the first step of application of the printing plate of FIG. 3 to the plate cylinder of FIG. 2;

FIG. 9 is a fragmentary sectional view of the plate cylinder showing a modified form of construction;

FIG. 10 is a fragmentary perspective view of the end of one of the clamping bars employed in the plate cylinder; and

FIG. 11 is a view similar to FIG. 10 but of the other clamping bar used in the plate cylinder.

P16. 12 is a fragmentary sectional view of a printing plate utilized in the invention.

FIG. 13 is a view similar to FIG. 12 but showing the printing plate with certain areas removed to leave upstanding cones.

Referring now to the drawing, and first to FIG. 1, the numeral 11 designates generally the frame for the press, which includes the usual side frames 11 and 12, suitably secured together by means of tie-rods 13, cross rods 14, etc, to provide a rigid structure. The frame provides journals for the various printing rolls, also in conventional fashion. As seen in FIG. 1, the web W proceeds around an idler roll 15 and then in wrapping engagement with an impression cylinder or roll 16, preferably constructed of steel. The web, after having passed around, i.e., traveled with, the impression cylinder 16, is conducted to additional finishing stations (not shown) for perforating, folding, etc.

When the web is on the impression cylinder 16, ink impressions or characters are transferred thereto from a blanket or transfer cylinder 17 which preferably is rubber-covered. The impressions are derived from a plate cylinder 18 which, like the cylinders 16 and 17, is journaled in the frame 111. From this, it will be understood that this showing is of offset printing.

To provide ink to the plate cylinder 18, the frame is equipped with a fountain roll 19 against which a ductor blade 20 operates, in conventional fashion. The ink from the fountain roll is transferred to the ductor roll 21 and thence to a longitudinally vibrating roll 22. The roll 22 in turn transfers its ink to distributing rolls 23 and 24, and these in turn relay the ink to a second vibrating roll 25. The ink is then transferred by means of form rollers 26 and 27 to the plate cylinder 18, more particularly, to the high point on the flexible plate covering, which can be better appreciated from a consideration of FIGS. 3, 12, and 13.

The printing plate is generally designated 28 and may include three layers of material. The first layer (to be positioned in contact with the surface of the plate cylinder 18) is a supporting surface and is constructed of a flexible, water-impervious plastic material 29. The outer layer 30 constitutes a water-soluble plastic material bonded to the inner layer 29 by means of a suitable adhesive binder 31. The plastic layer 30 has the property of being soluble in water until it has been exposed to light. Thus, in FIG. 13, it is seen that there are certain areas as at 3011 which have been removed, leaving upstanding cones as at 3012. This is provided through the superposition of a negative or other light filter, wherein the light passing through the negative creates the cones 30b and upon subsequent washing with water, the areas 30a are dissolved. Thus, a suitable printing plate is provided which normally has a thickness of the order of OBIS-0.017. It will be apparent, however that other printing plates such as brass-backed rubber plates may be advantage-ously employed in the practice of the invention.

The plate cylinder 18 which supports the flexible plate 28 is seen in FIG. 4 to include a longitudinally extending recess 32 having a dovetail configuration in transverse section. The peak of the dovetail-communicates with the periphery of the roll 18 as at 33, with the dovetail cross section being defined by outwardly converging walls 34 and 35. Hereinafter, when the term first wall is employed, it will refer to the wall 34, and the term second wall will refer to the wall 35.

Positioned within the longitudinally-extending recess 32 are two clamping members, a first clamping member 36 and a second clamping member 37 (see particularly FIG. 6). The second clamping member 37 bears against the second wall 35 and is urged thereagainst not only by the first clamping member 36 but also by the springs 38 which extend between the secondcla-mping member 37 and'the first wall 34, as illustratedin FIG. 6.. The

first member 36 is urged against the second member 37 by means of another group of springs 39 which also bear against the first wall 34, as seen in FIG. 7.'

For the purpose of mounting the springs 38 and 3%, the v first clamping member 36 is providedwithbores as at 40 and 41. The bores 44 are seen to extend through the vgenerally rectangular-shaped first clamping member36, while the bores 41 extend only partway through, as shown in FIGS. 6 and 7, respectively.

. der circumference), the foot-like portion 42 is a 30 projection', with the length of the foot being of the order of 7 A v 7 With the. construction shown, it is possible to advanta'geously utilize small diameter plate cylinders, i.e., of

Additionally, the first clamping member 36 is equipped with a' foot-like portion 42 which provides additional bearing between the first clamping member 36 and the base 32a of the recess 32. Froma consideration of FIGS. 4 and 1 1, it will be seen that the second clamping'member 37 is generally wedge or triangular-shaped intransverse section except for the portion 37a along one longitudinal corner being relieved to accommodate the footlike portion 42. 'In this connection, refer to FIG. 3 where it is seen that theend portions of the plate 28 are folded the order of 8 /2 to 11 inches, and thus print a web with a single repeat, and a plate can be changed herein in about one minute." Also, I find. that the use of the offset arrangement picturedin FIG. 1' gives superior printing and V with about one-half as much ink as the direct impression j technique normally employed.

downwardly as at 43. On a plastic plate, I have found 7 that scoring as at 44 facilitates an even bend or fold.

In operation, a folded end portion defined by the end 43a and the transverse score line 44a is positioned be tween the second clamping element 37 and the second face 35, as appears in FIG. 8. Thereafter, the roll lit'is rotated in thedirection of thearrow in FIG. 8 and the 7 a clamping elements 36 and 27, respectively (see FIG. 7).

Both clamping elements 36 and 37 are equipped with end slots as at relative to element 36"(see FIG. 10-) 1 which permit its being pried against the urging of the springs 39 so as to permit insertion of the trailing end fold 43b.

With the clamping members arranged as seen in FIGS 6 and 7, the springs 38 urge the generally rectangular shaped first clamping member 36 against the end portion 43b and also againstthe second clamping member 37. In l this'connection, it will be appreciated that the foot-like" portion 42 provides an advantageous additional bearing against the recess base 320' facilitating sliding movement of the member 36'so as to maintain the necessary clamping pressure.

The direction of rotation of the cylinder 18 is seen'in FIG. 6, and it is seen there that the folded portion 43b provides thetrailing edge, this being the portion inserted 7 between the elements 36 and 37. This is particularly effective when the blanket or transfer cylinder .17 is slightly oversize, which might otherwise tend to pull out the plate 28 in the portion folded as at 43bl V In actual practice, it is possible to fold the'plate28'a trifle short, so that a slight gap is 'maintained at 43b'evenrafterjthev plate is inserted.

It will be seen that the first clamping mernb er 36 is generally a parallelepiped, including opposed angles,

with the upper surface as at 46 (see FIG. 8)being ground to the curvature of the plate cylinder 18. movement of the first and second members 36; and 37 is restricted by means, of straps or plates 47 (see FIGS, 2

Lon gitudinal tion of anembodi-ment of the inventionhas been set down The advantageous sliding movement of the members 36 and 37 maintains optimal pressure on the ends of the thin printing plate, minimizing distortions, and this slid- Ying movement be'enhanced through the use of molybdenum disulfa-te'tape'on the unde-rsides of the elongated rnembers 36 and 37.

In FIG. 9, a modified form of construction is seen wherein the plate 28 is seen to have its tail portion 143 adhesively secured by means'of adhesive 149 to the upper surface of the clamping bar 36 wl1ich is carried by the plate cylinder 18. It will-be noted that in all of the illustra-t-ionss a smallga-p G, as designated in FIG. 9, occurs, and this is tolerable since in the printing provided by the'invention there are small spaces providedbetween adjacent repeats. It will be appreciated that with the plate mounting of the invention the gap-between printing repeats is kept to a bare minimum, occurring only at the apex ofthe clamping element 37'.

While in the foregoing specification a detailed descripfor the purpose of explanation, many variations inthe details hereing-iven may be made by those skilled in the art without departing from the spirit and scope of the'invention; a a I is equipped with an integral foot portion in contacting relation with the base wall of said recess.

and 4) which are suitably anchored by means of bolts 51 a at the two ends of the plate cylinder 18.

It will be appreciated that for suitable repeats it is necessary to print over the surface designated 46 in FIG. 8

Through the invention,'a, slight sliding movement of the element 36, necessary for holding the tail 43b of the print I claim: I 1. A printing plate cylinder, comprising an elongated cylindrical roll having a longitudinally extending dovetail-like recess equipped with a bottom wall and sidewalls converging to provide a constricted peripheral opening and adapted to secure the ends of a flexible printing plate, first and second elongated clamping membersin said recess in side-by-side relation, and. springfmeans in said recess urging said members toward one of said walls, said spring means including two sets of springs positioned in 'member to urge saidsecond member against said one Wall,

saidfirst member being equipped with transverse openings .with said other set of springs extending therethrough.

2. The structure of claim 1 in which said first member 3. A printing plate cylinder, Comprisingla roll having a longitudinally extending, dovetail recess in the periphery thereof, a first elongated-member in said recess and hav- Y ing generally a rectangular shape in transverse section," asecond elongated member in said recessand having generally a wedge shape: intransverse section, a first plurality of springs in said'recess urging said'first member against .said second member, a second plurality of springs in said recess urging said second member against the wall of said recess, said first member being equipped with transverse ing plate 28, does not appreciably alter the height, :i.e.,

radial distance, of the surface 46. The base of the dovef; tailed surface 320: is at a right angleto a center' line drawn from the middle of the surface 46 asinFIG. 8. ,Theoretically, the base 32;: ofithe dovetail and'the touching por -j tions of the elements 36 and 37 conform to an arc. of cur-' vature, the center. of Whichacorresponds to the'center of.

ope'ningswith saidsecond plurality of springs being housed therein, each member being .adapted to bear, against an end of a flexible printing plate, and slot'means atthe end of each member, for lever engagement to oversaid impression roll, a plate roll journaled in said frame for delivering ink impressions to said transfer roll, and roll means in said frame for delivering ink to said plate roll and for pressing the surface of said plate roll, said plate roll comprising a roll having a longitudinally-extending dovetail recess in the periphery thereof, a first elongated member in said recess and having generally a rectangular shape in transverse section, a second elongated member in said recess and having generally a wedge shape in transverse section, a first plurality of springs in said recess urging said first member against said second member and away from one of said dovetail walls, a second plurality of springs in said recess urging said second member against the other dovetail wall and away from said one dovetail wall, said first member being equipped with transverse openings with said second plurality of springs being housed therein, each member being adapted to receive an end of a flexible printing plate, slot means at the ends of each member for lever engagement to overcome said springs, and a flexible plate mounted on said plate roll with the ends thereof in clamping relation with said members.

6. A printing plate cylinder, comprising a roll having a longitudinally-extending, dovetail recess in the periphery 30 thereof equipped with a bottom wall and side walls converging to provide a constricted peripheral opening and adapted to secure the ends of a flexible printing plate, a

first elongated member in said recess and having a generally rectangnlar shape in transverse section, a second elongated member in said recess and having a generally triangular shape in transverse section, said second member being in confronting relation with one of said side Walls and said first member being in confronting relation with the other of said side walls, transverse passage means in said first member and spring means in said passage means extending beti een said second member and said other Wall, and additional spring means separate from the firstmentioned spring means interposed between said other wall and said first member whereby said members are independently manipulable to secure in independent fashion the said flexible printing plate ends.

References Cited by the Examiner UNITED STATES PATENTS 1,662,365 10/26 Lorenz 51194 2,154,757 4/ 39 Labombarde.

2,375,603 5/45 Willard 101--415.1 2,791,504 5/57 Plambeck.

2,797,638 7/57 Miller 10l-4l5.1 X 2,893,868 7/59 Barney 101-401.1 X

FOREIGN PATENTS 868,609 3/32 Great Britain.

666,356 2/52 Great Britain. 910,712 11/62 Great Britain.

ROBERT E. PULFREY, Primary Examiner.

EUGENE R. CAPOZIO, Examiner. 

1. A PRINTING PLATE CYLINDER, COMPRISING AN ELONGATGED CYLINDRICAL ROLL HAVING A LONGITUDINALLY EXTENDING DOVETAIL-LIKE RECESS EQUIPPED WITH A BNOTTOM WALL AND SIDE WALLS CONVERGING TO PROVIDE A CONSTRICTED PERIPHERAL OPENING AND ADAPTED TO SECURE THE ENDS OF A FLEXIBLE PRINTING PLATE, FIRST AND SECOND ELONGATED CLAMPING MEMBERS IN SAID RECESS IN SIDE-BY-SIDE RELATION, AND SPRING MEANS IN SAID RECESS URGING SAID MEMBERS TOWARD ONE OF SAID WALLS, SAID SPRING MEANS INCLUDING TWO SETS OF SPRINGS POSITIONED IN SAID RECESS, ONE OF SAID SETS OF SPRINGS EXTENDING BETWEEN THE OTHER CONVERGNG WALL AND SAID FIRST MEMBER TO URGE 